1. Field of the Invention
This invention relates to an image processing apparatus such as a copying apparatus or a facsimile apparatus, and in particular to an image processing apparatus which effects parallel-processing by a plurality of image processing means.
2. Description of the Prior Art
Heretofore, in an apparatus of this type, an image has been raster-scanned and read by a CCD or the like and has been subjected to image processing such as a binarizing process or tone processing. Recently, however, it has been proposed as the processing of this type to recognize the tone of the image on real time and selectively change over a processing suitable for the image tone to thereby reproduce the image.
However, in the digital copying apparatus according to the prior art, where an original is expressed in half tone like a photograph, dither processing is effected by the use of a process selecting key in accordance with the kind of the original, and if the original is a character original, a slice binarizing process by a predetermined threshold value is effected and thus, only the same processing has been effected for the entire area of the original.
On the other hand, if the image tone is discriminated on each area for an original comprising a mixture of characters and photographs, image reproduction faithful to the original will become possible by changing over the processing even in the same original. However, in spite of numerous techniques having already been proposed regarding the processing system of this type, they are all based on the two-dimensional information of the image with a desired pixel as the center. To accomplish said image tone recognition, means for storing therein the image information obtained by raster-scanning the image over at least two lines is indispensable and therefore, the scale of the circuit becomes bulky and accordingly, compactness of the apparatus has been desired.
Also, the processing algorism is complicated to discriminate accurately and accordingly, taking the scale of the circuit or the processing speed into consideration where the apparatus is constituted by hardware, the apparatus is not yet practical to such a degree that it is applicable to a versatile copying apparatus.